Chip's Chips Company Agrees to Supply Delicioso Café with All

Chip's Chips Company agrees to supply Delicioso Café with all the corn chips that it re?quires for a year.A sudden demand for ethanol results in a shortage of corn,and the price rises sharply.Chip's asks Delicioso to pay a higher price for the chips.This request is

A) invalid as an attempt at extortion or the so-called holdup game.
B) invalid under the preexisting duty rule.
C) valid as a risk ordinarily assumed in business.
D) valid due to the unforeseen difficulty of the sudden price increase.